Electromagnetic door holder and releaser



July 5, 1966 A. c. ULMAN ELECTROMAGNETIC DOOR HOLDER AND RELEASER 2 Sheets-Sheet 1 Filed May 27, 1965 INVENTOR.

fi/VJBFOSE C. L/L/WA/Y July 5, 1966 c, ULMAN 3,258,875

ELECTROMAGNETIC DOOR HOLDER AND RELEASER Filed May 2'7, 1965 2 Sheets-Sheet 2 M m4 /00 i-' 5. 4

as as w W POWER 3,258,875 ELECTROMAGNETIC DOOR HOLDER AND RELEASER Ambrose C. Ulman, San Diego, Calif., assignor t Barth Safety Equipment Co., line, Escondido, Calif., 21 corporation of California Filed May 27, 1965, Ser. No. 459,232 2 Claims. (Cl. 49379) This application is a continuation-in-part of my application Serial No. 303,759, filed August 20, 1963, now abandoned, which is a continuation-in-part of my application Serial No. 122,893, filed July 10, 1961, now abancloned.

This invention relates to a door holding and releasing mechanism, and more particularly to apparatus that closes a fire door in case of fire.

Background It is well known that in case of fire the free flow of air should be prevented as much as possible. To accomplish this fire doors are positioned in such a way that they can close various doorways and openings, in order to limit the amount of oxygen reaching the fire.

These fire doors and the door-closing apparatus take various forms. Regardless of which form is used, two conditions are imperative. The mechanism must be simple, and closing must be certain.

In the past, some doors have been closed manually, some are closed by having their own weight cause them to slide or roll down an inclined track, others are closed by counterweights, still others are closed by remotely positioned controls, and some are closed by spring actuating mechanism. However, no completely satisfactory, simple, and certain apparatus has been devised.

It is therefore the principal object of my invention to provide an improved fire door holding and releasing apparatus.

It is another object of my invention to provide an improved fail safe type of fire door closing mechanism.

It is still another object of my invention to provide a fire door closing apparatus that can be readily tested.

It is a further object of my invention to provide a fire door closing mechanism that incorporates a remote indicator to show whether the doorway is open or closed.

It is still further an object of my invention to provide a fire door holding and release mechanism that is selfresetting when the door is opened after a fire or a test.

It is an ancillary object of my invention to provide a fire door holding and releasing mechanism that is readily adaptable to swinging as well as sliding doors.

The attainment of these objects and others will be realized from the following specification, taken in conjunction with the drawings, of which:

FIGURE 1 is a representation of my invention with the fire door in an open position;

FIGURE 2 is an enlarged fragmentary view showing the operation of my door holding and releasing mechanism;

FIGURE 3 is a section on the line 3--3 of FIGURE 2;

FIGURE 4 shows my door holding and releasing mechanism applied to a swinging door;

FIGURE 5 is a schematic wiring diagram of the circuitry associated with my invention; and

FIGURE 6 is a fragmentary view of the lower part of the cover for the latching unit, looking in the direction of arrows 6 in FIG. 2 and showing the bird guard.

Detailed description of the invention As shown in FIGURE '1, a fire door 10 is suspended from a track I12 by hangers such as 14.

ice

Door 10 is normally withdrawn from doorway 16 to allow free passage therethrough. A counterweight 18 urges the door 10 to its right hand position, as shown by dotted lines 20, the urging being accomplished by a fireproof cable 22, which may be flexible steel wire or the like. In FIGURE 1, the urging of the counterweight is resisted by my door holding apparatus, which will be more fully described below.

Some applications employ a sloped track, so that the weight of the door 10 tends to close the doorway 16, but the weight is desirable to assure faster and more positive closing. A stop 22 of any suitable type, stops the door in the closed position.

My door holding apparatus comprises two basic units, a latching unit indicated generally by the reference numeral 30 and a holding and releasing electromagnetic unit indicated generally by the reference numeral 60.

Latching unit 30 consists of a generally rectangular housing having front wall 32, rear wall 34 and side walls 36. A conventional bracket 38 is suitably secured to rear wall 34 and is utilized to mount latching unit 30 on the edge of fire door 10.

Suitably journalled in side walls 36 of unit 30 is a mounting pin 40 which has fixed, thereto, intermediate its ends, a latching arm 42. Coiled around one end of pin '40 is a torsion spring 44, one end 46 of which is bent to engage latch 42 while the other end 48 rests against rear wall 34. Torsion spring 44 urges arm 42 in a counterclockwise direction as viewed in FIGURE 2.

As will be apparent from FIGURE 2 or 3, arm 42 extends through opening 52 in front wall 32. Spaced inwardly from the outer end of arm 42 is a latching notch 54 of any desired configuration. Leading into this notch is a sloping or cam surface 56, the purpose of which will be hereinafter described.

The holding and releasing electromagnetic unit 60, which is secured to wall 611, includes a generally rectangular sheet metal housing having a removable front wall '62, rear wall 64, top and bottom walls '66 and side walls 67 suitably secured together by fastening means 68. Unit 60 is provided with a bracket 69 attached to the rear wall 64 of the housing for securement to the supporting wall 61. An electromagnetic unit 70, of known construction and operation, is mounted on the inner surface of the back wall 64 adjacent the top thereof. Spaced from bottom wall 66, and suitably journal-led in side walls 67, and held against axial movement by any conventional means, is a shaft 72. Intermediate its ends the shaft has secured thereto a holding arm 74 which is generally U-shaped in cross section. A pad or section 76 of Armco iron or any similar material that will not retain residual magnetism, is mounted in the upper end of arm 74 in position to be contacted by the electromagnet 70. Bottom wall 80 of arm 74 is provided with a slot 82 adjacent its lower end, for receiving the free end of latching arm 42. The lower edge of slot 82 is formed with a curled lip or bead '84 formed integrally with the lever and forming a catch adapted to engage slot 54 in lever 42. A torsion spring 86, similar to spring 44, is mounted on shaft 72 and normally urges the arm 74 in a counterclockwise direction, whereby the'lever is maintained in latch arm catching position when the electromagnet is deenergized and prior to being engaged by the latch arm. Thus, upon attaching the unit 60 to the wall 61, latch catching position for the lever is assured. It is necessary then only to energize the electromagnet and it is thereafter held in latch arm catching position. If this spring was not provided, other means would have to be provided for moving the lever from the dotted line to the full line position.

The electrical circuitry is shown in FIGURE 5. A plurality of fuse type fire detectors 88 are connected in series with a power supply and the electromagnet 70. An indicator, illustrated as a lamp 90 in the same series circuit, when lighted, shows that the fire detectors have not been activated and the circuit is operating properly.

A normally closed test switch 92 is also connected as part of this same circuit in series with lamp 90. This test switch may be positioned wherever convenient and is normally closed. In testing, the test switch 56 is opened, thus opening the circuit and deenergizing the test lamp and electromagnet.

Referring now to FIGURES 1 and 2, door is shown in solid lines in the open position with the electric circuit closed and electromagnet 70 energized. In the event of a fire detectors 88 will respond thereto and the electric circuit will be opened thereby deenergiziug electromagnet 70. This will relieve the holding force on the lever 74 and the Weight of the door plus the weight of counterbalance 18 will urge the door to the right along track 12. Arm 74 will rotate in a clockwise direction, as shown by arrow 94 by reason of the force exerted on it by the engagement of slot 54 on arm 42 with edge 84. This movement will continue until arm 74 reaches the position 74 shown in dotted lines. At this position bead 84 is completely disengaged by notch 54 as shown by dotted lines 84' and door 10 is free to move unimpeded to the right or closed position, shown by the dotted lines in FIG- U-RE 1.

The bracket 38 is provided with slots 96 and is held in place on the door by screws 98 passing through the slots. By utilizing the vertical adjustment of the locking unit 30, the end 50 of the latching arm can be maintained spaced from the rear wall 34 of the housing. It is desirable to maintain the clearance between the end 50, the latching arm and the rear Wall 34 of the housing so that, should the wall 61 sag slightly, the latch arm can follow without becoming unlatched from lip or head 84.

Referring now to FIGURE 4, I have shown a slightly modified form of my invention. Door 100 is of the horizontal swinging type and is mounted on conventional hinges 102 to close in the direction of arrow 104. Door 100 may be urged to a closing position by any well known means such as springs or counterweights. The basic apparatus for holding the door 100 in an open position is similar to and operated in a like manner to that previously described. However door holding and releasing electromagnetic unit 60 is mounted by a suitable bracket to the face of wall 106 While the latching unit 30 is mounted to the opposing face of door 100.

A bird guard 106 formed of flexible and resilient material is fastened on the inside of unmovable front cover 62 of the housing of unit 60 by a strap 108 and rivets 110. This guard is provided with a plurality of slits for ready flexing thereof. The latch arm extends through the guard as is more clearly shown in FIGURE 2.

From the foregoing description it will be seen that my arrangement is of the fail safe type as far as the door closing action is concerned. Should there be a power failure, the fire door would immediately close, regardless of whether the power failure was caused by the fire or some other reason. Since the fire detectors are connected in series with the door holding circuit, if any one of these detectors is activated the corresponding door, or doors, will immediately close.

It will be apparent that my invention provides a simple, fool proof fire door holding and releasing apparatus, the operation of which can be easily tested at any desired time. Both embodiments are self resetting, that is, when the doors are opened after a fire or test, the latching and holding mechanism automatically goes into operation without requiring any particular attention, adjustment or setting.

It is understood that minor variation from the form of the invention disclosed herein may be made without depart-ure from the spirit and scope of the invention, and that the specification and drawings are to be considered as merely illustrative rather than limiting.

I claim:

1. In combination with a building wall having an opening and a fire door for closing the opening:

(A) a latching arm pivotally mounted upon the door;

(B) a housing, said housing including:

(1) a rear wall attached to the building wall,

(2) a removable front wall having an opening therein for receiving the latching arm,

(3) and side walls;

(C) holding means for the latching arm disposed within the housing, said holding means including:

(1) pivot means carried by a side wall of the housing,

(2) a lever pivotally carried by the pivot means and having an iron section adjacent the free end thereof, said lever having a slot interposed between the pivot means and the iron section for receiving the free end of the latching arm and forming an integral catch cooperating with the latching arm, said door and latching arm being biased normally toward catch releasing position,

(3) electromagnetic means attached to the rear wall of the housing, for holding said lever in latching arm catching position when energized, said means being disposed in magnetic cooperable relationship with the iron section of the lever,

(4) and a coil spring about said pivot means for holding said lever in latching arm and catching position when the electromagnetic means is deenergized and the latching arm is disengaged from the lever.

2. A combination as defined in claim 1, characterized to include:

(D) a second housing fixed to the door and having an opening, the latching arm being pivotally mounted in the second mentioned housing, said latching arm extending through the opening in the second mentioned housing.

References Cited by the Examiner UNITED STATES PATENTS 985,995 3/1911 Graham et a1 292-201 X 1,057,608 4/1913 Wurmb et a1. 1891947 X 1,199,199 9/ 1916 Mason 292-201 2,171,365 8/ 1939 Harding 292-201 2,604,789 7/ 1952 Derby et a1.

HARRISON R. MOSELEY, Primary Examiner.

W. E. HEATON, Assistant Examiner. 

1. IN COMBINATION WITH A BUILDING WALL HAVING AN OPENING AND A FIRE DOOR FOR CLOSING THE OPENING: (A) A LATCHING ARM PIVOTALLY MOUNTED UPON THE DOOR; (B) A HOUSING, SAID HOUSING INCLUDING: (1) A REAR WALL ATTACHED TO THE BUILDING WALL (2) A REMOVABLE FRONT WALL HAVING AN OPENING THEREIN FOR RECEIVING THE LATCHING ARM, (3) AND SIDE WALLS; (C) HOLDING MEANS FOR THE LATCHING ARM DISPOSED WITHIN THE HOUSING, SAID HOLDING MEANS INCLUDING: (1) PIVOT MEANS CARRIED BY A SIDE WALL OF THE HOUSING, (2) A LEVER PIVOTALLY CARRIED BY THE PIVOT MEANS AND HAVING AN IRON SECTION ADJACENT THE FREE END THEREOF, SAID LEVER HAVING A SLOT INTERPOSED BETWEEN THE PIVOT MEANS AND THE IRON SECTION FOR RECEIVING THE FREE END OF THE LATCHING ARM AND FORMING AN INTEGRAL CATCH COOPERATING WITH THE LATCHING ARM, SAID DOOR AND LATCHING ARM BEING BIASED NORMALLY TOWARD CATCH RELEASING POSITION, (3) ELECTROMAGNETIC MEANS ATTACHED TO THE REAR WALL OF THE HOUSING, FOR HOLDING SAID LEVER IN LATCHING ARM CATCHING POSITION WHEN ENERGIZED, SAID MEANS BEING DISPOSED IN MAGNETIC COOPERABLE RELATIONSHIP WITH THE IRON SECTION OF THE LEVER, (4) AND A COIL SPRING ABOUT SAID PIVOT MEANS FOR HOLDING SAID LEVER IN LATCHING ARM AND CATCHING POSITION WHEN THE ELECTROMAGNETIC MEANS IS DEENERGIZED AND THE LATCHING ARM IS DISENGAGED FROM THE LEVER. 